Two atrial peptides obtained from rat atria were characterized by M. G. Currie et al. and are described in the Science issue of Jan. 6, 1984. Atriopeptin I has the formula: ##STR2## wherein there is a bridging bond between the sulfhydryl groups of the two cysteinyl amino acid residues. Atriopeptin II has the same 21 residues plus the residues Phe and Arg at the C-terminal at positions 22 and 23, respectively.
Atriopeptins I and II are fragments of rANF(1-33), i.e. rat atrial natriuetic factor, as reported in FEBS Letters, 167, 2, 352-6, Feb. 1984. rANF and its fragments exhibit potent effects on kidney function and regional vascular resistance; they have natriuretic, diuretic and smooth muscle relaxant activities.
Human ANF(hANF), more specifically hANF(1-33), is reported in Biochem. Biophys. Res. Comm., 118, 1, 131-9 (1984) and is found to have similar properties.